1. Field of the Invention
The present invention relates generally to a gas laser having a discharge vessel within which is mounted a laser capillary.
2. Description of the Related Art
A gas laser is disclosed in German patent no. 25 06 707, and corresponding U.S. Pat. No. 4,081,762. The disclosed gas laser includes a laser tube of glass closed with metal end caps, the temperature coefficient of the metal end caps generally being matched to that of the laser tube. The metal end caps are less sensitive than the end sections of glass previously employed in gas lasers, and can accommodate mechanical stresses which arise, for example, from adjustment of the laser mirror.
However, the metal end caps can also transmit stresses to the glass tube with such intensity that breakage occurs at the junction. The metal caps, moreover, are subject to asymmetrical deformations during temperature fluctuations as a consequence of bushings, as well as pump stems which are connected to the metal caps. The asymmetrical deformations lead to misadjustment of the laser beam and, thus, to a considerable energy loss. As consequence of any different coefficients of expansion of the glass tube and the metal caps, changes in power during a warm-up period, which can last for up to fifteen minutes, are extremely disturbing for use in many applications.
The use of end pieces of sintered glass are known, for example, in flash bulbs.